Chromium/DM-FYI

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Chromium picolinate (CrPic) supplementation improves glycemic control in

patients with type 2 diabetes not adequately controlled while taking

sulfonylurea, according to the results of a randomized, double-blind study

reported in the August issue of Diabetes Care.

http://www.medscape.com/viewarticle/542296?sssdmh=dm1.206610 & src=nldne

" CrPic supplementation has been suggested to improve glycemia, but there are

conflicting reports on efficacy, " write , MS, RD, from the

University of Vermont in Burlington, and colleagues. " To provide a comprehensive

clinical evaluation of chromium, we conducted a randomized, double-blind,

placebo-controlled trial in subjects with type 2 diabetes and over a 10-month

period of observation, used established techniques to assess changes in insulin

sensitivity, body composition, and glycemic control. "

After baseline evaluation, 37 subjects with type 2 diabetes were treated with a

sulfonylurea (glipizide gastrointestinal therapeutic system, 5 mg/day) with

placebo for 3 months. These subjects were then randomized in a double-blind

fashion to receive for 6 months either the sulfonylurea plus placebo (n = 12) or

the sulfonylurea plus 1000 ?g of chromium as CrPic (n = 17). End points included

body composition, insulin sensitivity, and glycemic control at the end of the

3-month single-blind placebo phase and at study end.

The group receiving sulfonylurea/placebo fared worse than the sulfonylurea/CrPic

group in terms of increase from baseline in body weight (2.2 kg; P < .001 vs 0.9

kg; P = .11), percent body fat (1.17%; P < .001 vs 0.12%; P = .7), and total

abdominal fat (32.5 cm2; P < .05 vs 12.2 cm2; P < .10) from baseline. Compared

with the sulfonylurea/placebo group, the sulfonylurea/CrPic group had

significant improvements in insulin sensitivity corrected for fat-free mass

(28.8; P < .05 vs 15.9; P = .40), glycated hemoglobin levels (HbA1c; -1.16%; P <

..005 vs -0.4%; P = .30), and free fatty acids (-0.2 mmol/L; P < .001 vs -0.12

mmol/L; P < .03).

" This study demonstrates that CrPic supplementation in subjects with type 2

diabetes who are taking sulfonylurea agents significantly improves insulin

sensitivity and glucose control, " the authors write. " Further, CrPic

supplementation significantly attenuated body weight gain and visceral fat

accumulation compared with the placebo group.... The mechanisms for these

findings are not precisely known, but clinical research studies addressing

dietary intake, skeletal muscle fat oxidation, and insulin signaling are

ongoing. "

This study was supported in part by grants R55 DK060126 and R01 DK060126. The

costs of publication of this article were defrayed in part by the payment of

page charges, mandating that it must therefore be hereby marked " advertisement "

solely to indicate this fact.

Diabetes Care. 2006;29:1826-1832.

Learning Objectives for This Educational Activity

Upon completion of this activity, participants will be able to:

1.. Describe previous research of chromium supplementation among patients with

glucose intolerance.

2.. Identify the effects of chromium supplementation among patients with type

2 diabetes.

Clinical Context

Chromium remains a popular supplement for patients with obesity and type 2

diabetes, even though it has a mixed track record of efficacy for these

patients. In a study of 20 individuals with glucose intolerance by Gunton and

colleagues, which appeared in the March 2005 issue of Diabetes Care,

supplementation with 800 ?g of CrPic daily failed to improve subjects' body mass

index, waist circumference, degree of glucose intolerance, or cholesterol levels

when compared with placebo. The only significant difference between groups was

an increase in the serum chromium level in the active treatment group.

The authors of the current study examine the effects of CrPic supplementation at

a higher dose and for a longer follow-up period among a cohort of patients with

diabetes.

Study Highlights

a.. Adults between the ages of 25 and 75 years were eligible for study

participation if they had diabetes that was controlled with diet or a low dose

of oral medications. All participants had fasting plasma glucose levels between

125 and 170 mg/dL.

b.. Participants underwent a 4-week period for washout of any previous

diabetes therapy, followed by a 12-week period of treatment with long-acting

glipizide. They were then randomized to receive either placebo or 1000 ?g of

CrPic daily along with the glipizide. The randomized treatment period lasted 24

weeks.

c.. Study outcomes included insulin sensitivity, as measured by

hyperinsulinemic/euglycemic clamp testing after an overnight fast; body

composition, as measured by computed tomography and dual-energy x-ray

absorptiometry; and serum glucose, HbA1C, and lipid values.

d.. 25 participants underwent randomization, and 17 of the subjects were men.

The mean age of subjects was 59.7 years, and the mean body mass index was 30

kg/m2. The mean HbA1C level at baseline was 9.7%.

e.. Baseline values for urine chromium were nearly nondetectable, but levels

increased significantly among subjects receiving CrPic.

f.. By the end of the randomized treatment period, mean fasting glucose had

decreased by 31.0 mg/dL in the CrPic group, which was significantly superior to

the mean 11.3 mg/dL decrease in the placebo group. The mean decreases in HbA1C

were 1.16% and 0.44%, which represented another significant difference favoring

CrPic therapy.

g.. CrPic improved measures of glucose tolerance and insulin sensitivity

compared with placebo.

h.. The mean level of free fatty acids decreased in both the placebo and CrPic

groups, although CrPic was more effective in reducing these levels. Triglyceride

levels were similar between treatment groups.

i.. Participants receiving placebo gained weight and percent body fat during

the randomized treatment period, whereas subjects receiving CrPic experienced an

increase in fat-free mass vs baseline. Only subjects receiving placebo had

increases in total abdominal, visceral, and abdominal subcutaneous fat.

Pearls for Practice

a.. Chromium supplementation has a mixed record of efficacy in the management

of glucose intolerance based on previous research, including a negative trial

published in 2005.

b.. In the current study of patients with diabetes treated with a

sulfonylurea, CrPic significantly improved glucose control, insulin sensitivity,

and visceral fat accumulation vs placebo. Triglyceride levels were similar

between the placebo and CrPic treatment groups.

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Ortiz, RD

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